The applicant has proposed a catalyst-referred chemical processing system for processing a surface (surface to be processed) of a substrate by placing the substrate in an acid processing solution, placing an acid or basic solid catalyst in contact with or in close proximity with the surface of the substrate, and eluting surface molecules of the surface which is held in contact with or in close proximity with the solid catalyst into the acid processing solution (see Japanese laid-open patent publication No. 2008-121099). According to the catalyst-referred chemical processing system, the surface of the substrate (workpiece) is irradiated with light, preferably ultraviolet light, or a voltage is applied between the substrate and the solid catalyst, to promote oxidization of the surface for an increasing machining rate. The catalyst-referred chemical processing system makes it possible to planarize the surface of the substrate with only a chemical action while causing little damage to the surface of the substrate. However, it is generally difficult to planarize a surface of a single substrate made of a compound semiconductor containing an element Ga, for example, to a sufficiently highly accurate surface roughness within a practical given period of time.
Demands for finer and multi-layered interconnects for highly integrated semiconductor devices in recent years require that the surface of films such as metal films on the surface of substrates such as semiconductor wafers or the like be planarized to a high degree. To meet such demands, it has widely been customary to planarize the surface of films on the surface of substrates by removing surface irregularities therefrom according to chemical mechanical polishing (CMP). In a chemical mechanical polishing process, it is necessary while a film is being polished to monitor the polished state of the film in order to stop polishing the film at a desired position. Therefore, it has been the general practice to monitor the polished state of an electrically conductive metal film formed on a surface of a substrate by applying an inductive magnetic field to the metal film and detecting the rate of attenuation of an eddy current generated in the surface of the metal film with an eddy current sensor for thereby measuring the thickness of the metal film.
The applicant has proposed an apparatus for monitoring the polished state of a film formed on a surface of a substrate by applying light to a surface (surface to be polished) of a film on a surface of a substrate, breaking up the light reflected from the surface into spectral data with a spectrometer, and measuring the thickness of the film based on the spectral data (see Japanese laid-open patent publication No. 2004-154928).
The applicant has also proposed a polishing method of polishing a surface (surface to be polished) of a semiconductor substrate by holding the surface of the semiconductor substrate and a contact platen (polishing tool), at least the surface of which is made of a catalyst, in contact with each other and moving them relative to each other within a processing liquid, as a polishing method of precisely and efficiently polishing a semiconductor substrate of a hard-to-process material such as Sic, GaN, or the like (see Japanese laid-open patent publication No. 2009-117782). The contact platen comprises, for example, a base of molybdenum or the like and a catalyst of platinum or the like which is attached to a surface of the base.